Purification of unsaponifiable fractions of fats or oils



Patented May 14, 1946 PURIFICATION OF UNSAPONIFIABLE FRACTIONS OF FATS OR OILS Loran O. Buxton, Newark, N. J., assignor to National Oil Products Company, Harrison, N. J a a corporation of New Jersey No Drawing. Application April 28, 1944,

l Serial No. 533,256

(Cl. 167---8l) 11 Claims.

The present invention relates to the purification and concentration of the unsaponifiable fraction In U. S. Patent No. 2,318,749, there is disclosed a process for producing a fat-soluble vitamin concentrate which broadly consists of the steps of saponifying a fatty material such as a fish liver oil to yield a soap of a predetermined moisture content, adding a hydrocarbon or halogenated hydrocarbon solvent to the soap, and heating the solvent and soap to a temperature of about 60 or 70 C. The soap-solvent mass is then cooled to room temperature and a quantity of water added to facilitate the separation of the soap from the solvent. Thereafter, the soap layer is separated from the solvent layer and extracted with successive heating and cooling to room tem erature with successive quantities of additional solvent. Although the aforementioned process is successful in producing vitamin concentrates in a relatively high yield. large amounts of solvent are necessarily used, as it was thought preferable to actually dissolve lhe soap in the solvent upon heating, and the time involved for the process is relatively long. For example, the cooling of the mass to room temperature prior to the addition of the water to effect separation takes place over several hours, and the clean separation of the soap from the solvent after the addition of the water generally consumes an additional several hours time. Further, the relatively slow cooling and necessary agitation cause reabsorption of'the solvent and unsaponifiable material on the soap. If it is attempted to' cool the mass without stirring, the time involved in cooling is necessarily increased. Inasmuch as contact of the vitamin content with the soap tends to promote deterioration of the same. the resultant vitamin concentrate, when produced, has a relatively low potency when tested by the bio-assay method. In U. S. Patent No. 2,318,748, a somewhat similar process to that outlined has been disclosed, except that the saponification takes place in presence of a suit-able solvent.

In accordance with the U. S. patent application, Serial No. 486,214, it was discovered that the soap could be separated from the solvent at elevated temperatures, as, for example, from 40 to 80" C.

and preferably between 60 and 70 0., provided, as. was pointed out, that the total water content of the saponified mass was kept within a critical range of between 23 and 35 It has now been discovered, however, that in actual plant practice. the critical range varies substantially with the type of oil being treated. In other words. long chain acids present in an oil tend to make the character of the produced soap harder, while unsaturated groupings tend to make the produced soap softer. Even though a hard soap is produced. however, from a given oil, this type of soap also tends to occlude more of the unsaponifiable material, and it is therefore necessary to add water in order to change the character of the soap so that the same will have a looser structure. In the case of softer soaps, water must also be added to decrease solubility. However, if too much water is added to a soap, the soap tends to have an increased afiinity for the unsaponifiable material. even though the structure of the soap may be more desirable for extraction, and, therefore, it may be stated that the less water that can be used with any particular type of oil, the less solvent will be necessary for an efficient extraction.

Further, the higher the water content, the greater the tendency for the soap to emulsify in the solvent upon stirring, so asto render separation at the elevated temperatures involved in accordance with the present invention difilcult. It is for this reason that in any event in practicing the present process, agitation and stirring of the soap mass and extracting solvent be kept at a minimum consistent with efficient extraction.

In general, it has been now discovered that when proceeding with the hot extraction of the saponified-olls with a suitable solvent, the total moisture content of the soap can be varied from 12 to 35% and, in some instances, as high as However, the best manner of determining the quantity of water to be added is that such quantity of moisture be present in the soap so that the soap will be slightly soluble at temperatures just below the boiling point of the solvent used. For ethylene dichloride, the preferred solvent, this temperature is between 40 and 70" C. and preferably between and C. In other words, it has been discovered that if from 'to 5% of the soap, and preferably somewhat less than 1%, is soluble in the solvent, as, for example, ethylene dichloride, the character of the soap is such that a minimum amount of solvent can be used for the extraction of unsaponifiable matter and that further, if the moisture content of the soap is within this range, the separation of the soap layer from the solvent is substantially instantaneous so that the process of extraction process somewhat greater in plant practice than those produced when proceeding in accordance with the aforementioned prior patents, but the concentrate produced exhibits a general increase in actual potency as determined by bio-assay tests. Further, because of the ease of separation and extraction at these relatively high temperatures, the concentrates produced have been exposed to contact with alkali, i. e. soaps, for the shortest possible period of time so that peroxide formation with consequent oxidation losses are maintained at a minimum, i. e. the vitamin concentrates as produced in accordance with the present process are in general more stable.

It is one of the objects of the present invention, therefore, to provide an improved process for the production of vitamin concentrates by the saponification of various types of vitamin-containing oleaginous material followed by subsequent separation and extraction of the soaps formed.

A second object of the present invention is to tion may be effected by various alkalis, such as potassium hydroxide, sodium hydroxide, sodium carbonate, etc., although potassium hydroxide is preferred; may be carried out under various conditions, for instance in solvent solution, with or without the presence of catalysts, etc.; and may be carried out either completely or to any desired degree, for instance, a less than stoichiometrical quantity of alkali may be employed so provide a process for the separation of saponified material from unsaponifiable material present in vitamin-containing oils, said separation and extraction of the material being effected in the shortest possible time and with a minimum of solvent.

A third-object of the present invention is to provide a process for the preparation of vitamin concentrates by saponifying fish liver oils and the like with a suitable alkali followed by the hot extraction of the soaps produced by means of a suitable solvent, wherein the moisture content of the soap is so regulated that a relatively small amount as, for example, from to 5% of the soap is soluble in the solvent used, whereby the extraction and separation of the unsaponifiable from the soap takes place in a minimum amount of time and with the use of a minimum quantity of solvent.

Other objects and advantages of the present invention will become apparent from the present specification and claims.

In carrying out the process of the invention, any suitable saponifiable oil or fat from which the recovery of the unsaponifiable fraction is desired, may be used in effectuating the purposes of the invention. The unsaponifiable fraction of various animal, vegetable and marine oils and fats contains valuable by-products when separated from their fatty vehicle Many oils contain sterols and more particularly the fat-soluble vitamins A, D and E and pro-vitamin A. While the present invention may be applied to various oils, it has particular value in the production of the fat-soluble vitamin concentrates which are derived from fish liver oils andv certain animal and vegetable oils; the vitamin A and/or D containing oils include, among others, the oils produced from various fish and their livers, such as cod, sardine, halibut, tuna, shark, dogfish, ling cod, pollack, sword, pilchard, whale, and other fish. Pro-vitamin A may be concentrated according to the invention from various vegetable oils, such as palm oil and carrot oil, and vitamin E may be recovered from wheat germ, rice bran and like oils. The unsaponifiable fractions of various other oils including rice bran oil, soya. bean oil and the like are valuable products in and of themselves and may be recovered in accordance with the process of the invention.

In accordance with this invention, the first step comprises the production of a saponified mass containing soaps and unsaponifiable matter by treating a suitable fat or oil with alkali. The resultant saponified mass, either immediately or after certain intermediate manipulations, is extracted with a solvent at high temperature and with the total water content adjusted within the critical range above set forth. The saponificaas to secure selective saponification of only certain components in the oil. Moreover, the high temperature extraction need not be the first extraction, separation or other manipulation carried out upon the saponified mass; for instance, a saponified mass can be extracted with solvents one or more times in the ordinary way at low temperatures, followed (with adjustment of the water content to the critical range if it is not already within that range) by one or more solvent extractions at high temperature. Nor is it essential that the extraction be carried out by means of solvents freshly added after the saponification; for instance, all or a part of the solvent may have been present during the saponification. In brief, the salient features of this invention consist in first preparing, from an oil containing unsaponifiable matter, a mass which contains, in intimate contact, soaps of the saponifiable matter in the oil, the unsaponiflable matter in the oi1,.the selected solvent, and water, in such amount that the soap is slightly soluble in the solvent at a temperature just below the boiling point thereof. The temperature of this mass is then raised, if it is not already raised, to a temperature between about 40 and about 0. (preferably between about 60 and about 70 C.) and the solvent, containing dissolved unsaponifiable matter, is mechanically separated from the mass. The water necessary to render the soap only slightly soluble in the solvent may be added either with the alkali or after saponification.

The extraction steps according to this invention may be carried out by the use of any suitable hydrocarbon or halogenated hydrocarbon solvent or mixture thereof, it being preferred. however, to use a halogenated hydrocarbon solvent, and particularly ethylen dichloride. This solvent, besides effectively extracting unsaponifiable matter from saponified masses, has the further advantage of high density, so that it spontaneously settles to the bottom after any extractive manipulations and can readily be drawn off. However, other solvents such as trichlorethylene, trichloroethane, heptane, octane. methyl cyclohexane, carbon tetrachloride and the like may be used. Preferably, the amount of solvent used is limited, inasmuch as the soap, as before pointed out, is soluble to a slight extent therein. The amount of solvent used for each extraction may vary between an amount equal to the weight of the original oil being treated, to about sixtimes the quantity of oil being treated. In general, the amount of solvent used for the first extraction is somewhat greater than that used for subsequent extractions. Preferably, for the first extraction in a typical case, an amount of solvent about four times the amount of the oil is used; and for subsequent extractions, this quantity of solvent may be reduced untilit i about equal to the amount of oil being treated.

As before pointed out, when carrying out the process at the preferred range of temperatures.

the structure of the soap exhibits a minimum affinity for the unsaponifiable material and solvent, and it has been discovered that when proceeding in accordance with the present process. only from 4 to 8 extractions are necessary to remove all of the unsaponifiable material from the soap. Each of these extractions takes place in a minimum of time, since the separation of the soap from the oil and solvent is substantially instantaneous. Preferably during extraction, agitation is kept at a minimum.

In proceeding in accordance with the present process, the saponification may take place in the conventional manner, either with the" addition of a suitable saponification catalyst such as an alcohol, or without, such addition. Heat is usually generated during saponification, or the mass may be heated to a slight extent so that the final saponification mass is already above room temperature. If the temperature of the mass is below the temperature desired for extraction, it may then be heated slightly, or preferably, the solvent is added in a hot condition. If an addition of water is necessary to adjust the water content of the soap so that it is only slightly soluble in the solventyit is added after the solvent has been mixed with the oil so that emulsification due to prolonged agitation may be minimized and preferably ina heated condition so that at no time is the mixture of solvent and soap substantially cooled. The soap is then separated from the solution of unsaponiflable material in the solvent and the soap mass again treated with an additional quantity, as before set forth, of heated solvent, so that the temperature in all extractions in the case where ethylene dichloride is used is preferably approximately 60 to 70 0.; although as before stated, the amount of water in the soap is adjusted so that a small quantity.

as, for example, lrom to and preferably somewhat less than. 1%. of the soap is dissolved in the solvent, it is to be understood that this is true only of the initial extraction, and if the amount of water is thus adjusted, a much lesser quantity is usually dissolved during subsequent extractions. Violent and prolonged agitation is also avoided during the subsequent extraction. After the extractions have been separated, they may then be combined and the small amount of dissolved soap removed by cooling theextracts. Inasmuch as the amount of soap is very small in quantity, the amount of unsaponifiable material entrained in the soap upon cooling is also negligible in amount.

When other solvents than ethylene dichloride are used, the temperature may be somewhat higher than that mentioned and in general limited by the boiling point of the specific solvent. In no case. however, should the temperature used be below about 40 C. as the structure of the soap, as before stated, renders quick separation and extraction difiicult.

The present invention is illustrated but is not intended to be limited by the following examples.

Example I 1005 pounds of Mexican shark liver oil having a vitamin A content of 37,500 units of vitamin A per gram were saponified with 362 pounds of concentrated aqueous potassium hydroxide. It is to be noted that the 362 pounds were equivalent to the desired percentage of saponiflcation of the saponifiable material, which was 95%. The saponification was performed while stirring in a kettle and proceeded rapidly. The temperature at the end of about 30 minutes was about water with the soap and ethylene dichloride.

55. The percentage of water in the formed soap was approximately 13.8%. Thereafter, 500 gallons 5200 pounds) of ethylene dichloride, preheated to a temperature of 65 C., were added over a period of 15 minutes while stirring rapidly. The stirring was then stopped and 25 pounds of water added with a minimum amount of stirring necessary for thoroughly admixing the A sharp separation or the ethylene dichloride extract and the soap took place almost instantaneously and removal of the ethylene dichloride portion was begun. At the beginning of the removal, it was observed that a somewhat larger amount of soap was soluble in the solvent than desired. 'I'hereupon, 25 more pounds of water were added, and the mass was again slightly stirred. The extraction was then finished, and

the ethylene dichloride extract removed. The average actual temperature of the combined ethylene dichloride and soap mass during this extraction was approximately 60 C. After the first extraction, five more extractions were carried out with successive amounts of hot ethylene dichloride. Howevenonly 300 gallons of ethylene dichloride were used for each successive extraction. It is to be noted that after the fourth extraction, the extracts were colorless, indicating that most of the unsaponifiable matter had been extracted. After the first extraction, the stirring, as each batch of ethylene dichloride was added. was limited to 1-2 minutes in order toavoid any danger of the soap, which now contained approximately 16.8% of water, from emulsifying which would have rendered separation of the soap and ethylene dichloride layers more difficult. With minimum stirring, the stratification of the soap and ethylene dichloride was almost instantaneous, and the removal of the ethylene dichloride could be effected quickly. The ethylene dichloride extracts were combined and cooled to remove the small amount of soap dissolved therein. The amount of soap dissolved in the combined extracts was approximately 8 pounds. The ethylene dichloride was then removed by vacuum distillation to produce a vitamin concentrate. The following yields were obtained:

Input vitamin A-unsup. basis- L s..., .Hfi-i Output yield (unsap.) .pounds... ur.

Output yield vitamin A i/s insu t Output yield vitamin A .7 .....p|-r cent 10mm oi vitamin 1250 pounds of another lot of Mexican shark liver oil having a vitamin A content of 37,700 units of vitamin A per gram were saponified with sufficient concentrated aqueous potassium hydroxide to saponify of thesaponifiable mainput weight. oil.

i231] Input vitamin --unsap. basis.

.. pounds liar Output yield tunsap.) at 780,000 poigram or r 20,953 Lsnul. o r .pounds. 59,22."-

( utput yiv vitamin A -9. "per cent" 98.0.-

The present application is a continuation inpart of U. 5. application, Serial No. 486,214.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

l. A process for producing fat-soluble vitamin concentrates from oleaginous vitamin-containing materials which comprises saponlfying the oleaginous material to produce a soap mass, extracting the soap mass with a solvent selected from the class consisting of hydrocarbons and halogenated hydrocarbons while maintaining the temperature of the solvent and soap from about 40 C. to just below the boiling point of the solvent and the water content of the soap at such an amount that the soap is slightly soluble in the solvent and separating the warm solvent extract from the warm soap.

2. A process for producing fat-soluble vitamin concentrates from oleaginous vitamin-containing materials which comprises saponlfying the oleaginous material to produce a soap mass, extracting the soap mass with ethylene dichloride while maintaining the temperature otthe solvent and soap between 40 and 80 C. and the Water content of the soap at such an amount that the soap is slightly soluble in the solvent and separating the warm solvent extract from the Warm soap.

3. A process for producing fat-Soluble vitamin concentrates from oleaginous vitamin-containing materials which comprises saponifylng the oleaginous material to produce a soap mass and successively extracting the soap mass with portions of solvent ranging from about 1-1 to about 6-1 as compared to the weight of the original material, said solvent being selected from the class consisting of hydrocarbons and halogenated hydrocarbons. while maintaining the temperature of solvent and soap from about 40 C. to just below the boiling point of the solvent and the water content of the soap at such an amount that the soap is slightly soluble in the solvent, separating each of the warm solvent extracts from the warm soap and combining the extracts.

4. A process for producing fat-soluble vitamin concentrates from oleaginous vitamin-containing materials which comprises saponlfying the oleaginous material to produce a soap mass, extracting the soap mass with a solvent selected from the class consisting of hydrocarbons and halogenated hydrocarbons, while. maintaining the temperature of the solvent and soap from about 40" C. to just below the boiling point of the solvent and the water content at such an amount that the soap is soluble to an extent of about to 5% in the solvent and separating the warm solvent extract from the Warm soap.

5. A process for producing fat-soluble vitamin concentrates from oleaginous vitamin-containing materials of marine origin which comprises saponifying the material to produce a soap mass, extracting the soap mass with a solvent selected from the class consisting of hydrocarbons and halogenated hydrocarbons while maintaining the temperature of the solvent and soap from about 40 C. to just below the boiling point of the solvent and the water content of the soap at such an amount that the soap is slightly soluble in the solvent and separating the warm solvent extract from the Warm soap.

6. A process for producing fat-soluble vitamin concentrates from fish liver oils which comprises saponifying a fish liver oil to produce a soap mass. extracting the soap mass with ethylene dichloride while maintaining the temperature of the solvent and soap between 40 and C. and the water content of the soap at such an amount that the soap is slightly soluble in the ethylene dichloride and separating the warm ethylene dichloride extract from the warm soap.

7. A process for producing fat-soluble vitamin concentrates from fishliver oil which comprises saponifying the fish liver oil with potassium hydroxide to produce a soap mass and successively extracting the soap mass with portions of ethylene dichloride ranging from about 1-1 to about 6-1, as compared to the weight of the fish liver oil, while maintaining the temperature of ethylene dichloride and soap between 60 and 70 C. and the water content of the soap at such an amount that the soap is slightly soluble in the ethylene dichloride and separating the warm ethylene dichloride extracts from the warm soap.

8. A process for producing fat-soluble vitamin concentrates from fish liver oil which comprises saponifying the fish liver oil to produce a soap mass, extracting the soap mass with ethylene dichloride while maintaining the temperature of the ethylene dichloride and soap at between about 40 to 80 C. and the water content of the soap at such an amount that slightly less than 1% of the soap dissolves in the ethylene dichloride and separating the warm ethylene dichloride extract from the warm soap.

9. A process for producing fat-soluble vitamin concentrates from fish liver oil which comprises saponifying the fish liver oil with aqueous potassium hydroxide to produce a soap mass. extracting the soap mass with ethylene dichloride while maintaining the temperature of the ethylene dichloride and soap at between about 40 to 80 C. and the water content of the soap at such an amount that slightly less than 1% of the soap dissolves in the ethylene dichloride, and separating the warm ethylene dichloride extract from the warm soap.

10. A process for producing fat-soluble vitamin concentrates from fish liver oil which comprises saponlfying the fish liver oil to produce a soap mass, extracting the soap mass with ethylene dichloride while maintaining the temperature of the ethylene dichloride and soap at between about 40 to 80 C. and the water content of the soap at such an amount that slightly less than 1% of the soap dissolves in the ethylene dichloride and separating the warm ethylene dichloride extract from the warm soap, cooling the ethylene dichloride extract to separate the soap dissolved therein. and removing the ethylene dichloride from the extract.

11. A process for producing fat-soluble vitamin concentrates from fish liver oil which comprises saponifying the fish liver oil with potassium hydroxide to produce a soap mass. successively extracting the soap mass with portions of ethylene dichloride ranging from about 1-1 to about 6-1, as compared to the weight of the fish liver oil, while maintaining the temperature of the ethylene dichloride and soap between 60 and '70 C. and the water content of the 5:03p at such an amount that the soap is slightly soluble in the ethylene dichloride, separating the warm ethylene dichloride extracts from the warm soap. combining the extracts, cooling the combined extracts to separate the amount of soap dissolved therein and removing the ethylene dichloride from the extracts.

LORAN O. BUXTON. 

